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Fire-safety based Ship Design Using Consequence Analysis Tools Case Study : Nile Floating Hotels

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Title: Fire-safety based Ship Design Using Consequence Analysis Tools Case Study : Nile Floating Hotels


1

International Marine and Offshore Engineering
Conference 34 September 2014 Al JubailKingdom
of Saudi Arabia
Fire-safety based Ship Design Using Consequence
Analysis Tools Case Study Nile Floating Hotels
A. M. Salem, E. M. Dabess, A. A. Banawan and H.
W. Leheta Alexandria University, Egypt
2
Objective Of the work
  • The objective of this work is to analyze the
    consequences of a cabin fire scenario on board
    Nile floating hotels by using Fire and evacuation
    simulation program in order to propose new
    alternative designs/arrangements that are assumed
    to have an equivalent or higher level of fire
    safety than the existing design.

3
Introduction
  • Nile-floating hotels are passenger ships
    operating in the mild environment of the River
    Nile on short cruises from Aswan to Luxor, or on
    long cruises from Aswan to Cairo.

4
Introduction
  • These trips have acquired popularity among
    tourists and have become one of their popular
    destinations, so are considered of important
    impact on the Egyptian economy.
  • Unfortunately, the fleet of Nile-floating hotels,
    which consists of about 280 units, is subjected
    to many types of accidents which not only
    harmfully affect the national income but also
    affect the safety of life.
  • Statistical analysis of collected data of such
    accidents that occurred during the last 10 years
    showed that

5
Introduction
  • Although of being ranked third, fire accident
    aboard a Nile floating hotel with many crew and
    passengers on board is a potential catastrophe.

6
Introduction
  • The current fire safety design of Nile-floating
    hotels follows the national regulations of the
    Egyptian Authority for River Transport (RTA), and
    it seems that these descriptive regulations are
    not sufficient to prevent such accidents from
    recurring.
  • This may lead to disasters with bad effect on the
    reputation of Nile tourism and the national
    economy of Egypt.

7
Introduction
  • Fire products affect the evacuation progress,
    resulting in incapacitation and death.
  • These lethal cases mostly happen in spaces
    connected through small paths and corridors like
    accommodation spaces, where toxic smoke has high
    potential to fill the whole domain in short time.

8
Introduction
  • So, a fire scenario that is common to occur in
    accommodation spaces on board passenger ships as
    well as Nile-floating hotels was studied by using
    the integrated fire and evacuation simulation
    program FDSEVAC, namely (FDS 5.5.3 EVAC
    2.2.1).
  • A series of simulations was conducted involving
    an existing design of such accommodation space as
    well as four alternative designs/arrangements
    that are assumed to have an equivalent or higher
    level of safety than that of the existing design.

9
Consequence Analysis Process
  • Fire consequence analysis tools can be used to
    compare the fire safety level of an alternative
    designs violating the prescriptive regulations
    against an existing design that follows the
    prescriptive regulations.
  • Due to lack of information needed to conduct a
    frequency analysis, which is the core of any fire
    risk assessment, it is decided to base the
    comparison on the number of fatalities which is
    the output of the consequence analysis.

10
Case Study
  • An accommodation deck onboard an existing Nile
    floating hotel, which is designed to carry 158
    passengers occupying 66 cabins and 3 suites
    distributed on its 4 decks, is considered as a
    case study.

11
Case Study
  • The accommodation deck under consideration has a
    length of 56.4 m, width of 14.2 m, and height of
    2.5 m, and is arranged such as to accommodate 26
    cabins and 2 suites connected via a 1.2 m wide
    longitudinal corridor.
  • Walls and ceilings are consisting of three
    layers
  • - PVC paint layer,
  • - galvanized steel layer and
  • - Rockwool insulation layer

12
Design Fire Scenario
  • The fire is assumed to break out in a 2 m2 bed
    mattress located in cabin 1 and is assumed to be
    unaffected by any fire fighting action.
  • The door that connects the cabin of fire origin
    with the corridor is assumed to be open all the
    time, while the cabin window is assumed to be
    closed.
  • The smoke will propagate quickly into the
    corridor causing a worst condition inside the
    cabin of fire origin as well as along the
    corridor.
  • The close location of Cabin 1 to one of the main
    exits, in addition to the ventilation conditions,
    make the fire scenario described above the
    worst-case fire scenario that could occur in such
    deck arrangement.

13
Design Fire Scenario
  • The available collected data of the Nile floating
    hotels showed that about 50 of the existing
    ships are not equipped with an Automatic Fire
    Suppression System (AFSS)
  • So the existing design of the accommodation deck
    under consideration is also not equipped with
    AFSS. This would worsen the fire scenario under
    consideration.

14
Fire and Evacuation Simulation Parameters
  • The mesh used within the CFD model (FDS) has
    divided the domain under consideration into
    284,000 cells each cell has the size of (0.2 x
    0.2 x 0.2) m3.
  • A total number of 163 measurement devices (154
    inside the corridor and 9 inside Cabin of fire
    origin) are placed at a height of 1.6 m to record
    temperature, CO, CO2, O2, fractional effective
    dose, smoke layer height, volume fraction and
    smoke obscuration at every time step.
  • The toxic effects of gaseous fire products are
    treated in this study by using the fractional
    effective dose (FED) concept which should not
    reach the incapacitation level FED1.

15
Fire and Evacuation Simulation Parameters
  • The properties of agents used in the evacuation
    simulation are

16
EXISITNG DESIGN (CASE A)
  • Smoke spread quickly into the corridor and
    reached the nose level of agents trying to
    escape. This lead to a rapid accumulation of
    toxic effects which is translated into reduction
    in agent speeds.
  • As an outcome, 17 fatalities (out of 56
    passengers) have occurred because they were
    unable to reach a place of safe refuge before
    reaching the untenable condition.
  • So, in order to enhance this situation, the
    authors decided to examine some alternative
    designs that can increase the level of fire
    safety within the domain of concern.

17
First Alternative Design (Case B)
  • In this case, it was decided to increase the
    corridor clear width from 0.9 m to 1.3 m in order
    to reduce the initial agent density, which is
    expected to result in reduction of congestion and
    queuing of occupants during the evacuation
    process.

18
Second Alternative Design (Case C)
  • In this case, it was decided to replace Cabin
    12, which is located midway between the cabin of
    fire origin and the only available exit (Exit 1),
    by a new second exit (Exit 2).
  • It is expected that the time needed for
    evacuation of the passengers will be decreased,
    resulting in much less congestion and queuing in
    the corridor.

19
Third Alternative Design (Case D )
  • As a third alternative design, it was decided to
    use a smoke extraction system consisted of 6
    smoke extractors with capacity of 0.6 m3/sec
    each, mounted into the corridor ceiling.
  • It is expected that this alternative design be
    able to maintain a smoke-free clear path for the
    passengers to escape safely from the available
    exit by extracting the smoke at reasonable rate.

20
Fourth Alternative Design(Case E )
  • Finally, it was decided to examine the effect of
    using a fire suppression system on the level of
    fire safety within the domain.
  • The system is a residential wet-pipe sprinkler
    system consisting of 18 pendant sprinkler heads
    (16 in the corridor and 2 in the cabin of fire
    origin).

21
DISCUSSION of RESULTS
22
Discussion of Results
23
Concluding Remarks
  • Fire and Evacuation Simulation models are
    essential tools that could help ship designers
    analyze the consequences of given fire scenarios
    and evaluate the level of safety of their
    designs, hence reach the design, which has a
    level of safety that is as high as reasonably
    practicable.
  • Consequence analysis tools could also help the
    authorities having influence in changing,
    enhancing or developing regulations concerning
    the fire safety design of Nile-floating hotels.

24
Concluding Remarks
  • Among the four tested alternative designs, the
    design that showed the best result was the one
    with sprinkler system installed. This would
    support the conclusion that the 50 of the fleet
    of Nile-floating hotels that work without
    sprinkler systems are in great danger if a
    similar fire scenario as the one considered
    occurs.

25
Concluding Remarks
  • Instead of giving relaxations to the owners of
    that part of the fleet of the Nile-floating
    hotels which are sailing without sprinkler
    systems installed onboard, and in order to save
    the lives of their passengers, the authors
    advise licensing this type of ship to either
    force the ship-owners to install sprinkler
    systems or allow them to select alternative
    design/arrangement with an adequate level of
    protection against fires.

26
Concluding Remarks
  • The authors recommend studying the effect of
    merging one or more of the control options used
    in the alternative designs tested in this study
    expecting that the merged designs will have
    better fire safety level.

27
Thank You for Your Attention
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